Carburetor



Nov. 29, 1932. M. MIENNESSON CARBURETOR Filed Men 19. 1951 M We,

Patented Nov. 2 9, 1932 UNITED STATES PATENT OFFICE mAncEL MENNESSON, or NEUILLY-SUR-SEINE, FRANCE, :ASSIGNOB- 'ro Esocmrn ANONYME soLEx," or NEUILLY-sUR-sEmE, FRANCE, A CORPORATION or FRANCE CARZBURETOB Application flled larch 19, 1931, Serial No. 523,912, and in Belgium April 1, 1930.

The present invention relates to carburetors, and, more particularly, to those of the so called down-draft type.

In down-draft carburetors, as at present manufactured, it is found that the liquid fuel discharged from the nozzle frequently adheres to the outer wall thereof as it progresses into the mixing chamber so as to prevent a proper mixture to be formed.

One of the objects of the present invention is to provide a special form of nozzle assembly which,-in operation, prevents liquid discharged from the nozzle from adhering to the outer wall thereof.

Further objects will appear in the course of the detailed description now to be given with reference to the accompanying drawing in which the single figure represents a partial, axial section through one illustrative embodiment of the invention.

Referring to the drawing, there is shown, a carburetor assembly of the down-draft type composed of the following elements: an air inlet 1 provided with a Venturi tube 2 of usual design; a butterfly valve 3 positioned to simultaneously control the main and auxiliary (slow speed) mixing chambers; a support 4 for the nozzle held in spaced relation to the walls of the mixing chamber by a plurality of webs, 5, 6 of as small a section as possible whereby the reduction in the effective dimensions of the mixing chamber is a minimum; a fuel'supply passage 7 communicating with a constant level chamber in a manner to be described further on; a passage 8 adapted to supply combustible to an auxiliary or slow speed nozzle 21 formed in a plug 21; a main nozzle assembly composed of an outer tube 9 communicating with a passage 7; an inner tube 10 provided with a plurality of orifices 11 and formed to present a lurality of passages 12 permitting fuel to e fed frcm passage 7 into the space limited by tubes 9 and 10, said tube communicating at its upper extremity with the atmosphere, a cap 13 threadedly engaging with tube 9 and adapted to maintain tube 10 in position, said cap being provided withdischar e orifices 14 and 15 limited on opposite si es (1) by a conical surface 17 forming a sharp angle overhanging the discharge orifices and (2) a sharp an- I gled shoulder 16 extending outward beyond the outer surface of tube 9, and a plurality of passages 20 adapted to feed fuel to passage 8; a plug 19 provided with :a calibrated oriates in the following manner: Assuming-that the constant level chamber has been regulated at the level indicated by dotted line ab, i. e., very close to that of discharge orifices 1415, combustible will flow into passage 7 via plu 19 and calibrated orifice 18 so as to fill the space between tubes 9 and 10 at the same time passage 8 is filled and discharges fuel through auxiliary nozzle 21 under the action of the air aspirated through passage 22; when the throttle is open, the fuel contained in the space between tubes 9 and 10 forming an emulsive mixture with the air entering through orifice 11 is aspirated through discliargeorifices 1415 and is deviated by portions 16 and 17 into a zone lying between venturi 2 and tube 9 whence it passes valve 3 without any possibility of contact of the fuel with the outer surface of tube 9.

What I claim is 1 In a down-draft carburetor assembly,

including an air intake, a venturi, and a mixing chamber provided with avalve, a nozzle assembly comprising a pair of tubes positioned in spaced relation to one another and adapted toreceive liquid fuel in the space therebetween, and a cap coacting with said pair of tubes and having a discharge orifice formed therein, said discharge orifice being limited by a surface extending into the mixing chamber beyond the outer of said pair of tubes.

2. In a downdraft carburetor assembly including an air intake, a venturi, and a mixing chamber provided with a valve, a nozzle assembly comprising a pair of concentric tubes positioned in spaced relation to one another and adapted to receive liquid fuel in the space therebetween, the inner of said tubes havinga series of orifices formed in the 5 Wall thereo communicating withthe atmosphere, "and a cap coacting with said pair of tubes and having a discharge orifice formed therein, said discharge orifice being limited by a surface extending into the mixing cham- 0 her beyond the outer of said pair of tubes.

3. In a downdraft carburetor assembly including an air intake, a venturi, and a mixing chamber provided with a valve, a nozzle comprising a pair of concentric tubes positioned in spaced relation to one another and adapted to receive liquid fuel in the space therebetween, the inner of said tubes having a series of orifices in the walls thereof communicating with the atmosphere, and a cap coacting with said pair of tubes and having a discharge orifice formed therein, said discharge orifice being limited on the downstream side by a surface overhanging the outer of said pair of tubes and on the upstream side by a surface of increasing section.

4. In a downdraft carburetor assembly including an air intake, a venturi, and a mixing chamber provided with a valve, a nozzle assembly comprising an inner longitudinal wall having a plurality of orifices formed therethrough communicating with the atmosphere, an outer longitudinal wall positioned in spaced relation to said inner wall, said inner and outer walls being adapted to receive liquid fuel therebetween, said outer wall having a discharge orifice formed in the upper por'tion thereof, said discharge orifice being limited by a surface overhanging the remaining portions of said outer wall, and

'an end transverse wall enclosing the space between said inner and outer walls at a point adjacent said discharge orifice, said end wall having an outer surface of increasing section.

In testimony whereof I afiix my signature.

* MARCEL MENNESSON. 

